package homework.api03.exercises01;

import jdk.nashorn.internal.runtime.OptimisticReturnFilters;

import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo5 {
    public static void main(String[] args) {
        Collection<String> c = new ArrayList();
        c.add("one");
        //c.add(123);编译错误,123不是String类型
    }
}
